1. Technical Field
The technical field relates to a hydraulic valve arrangement technique of a mold functional component, particularly to a two-stage hydraulic booster device for mold functional components.
2. Related Art
In order to do the auto cutting or pushing and squeezing plastic pieces, the inside of the traditional male mold and female mold used for forming the plastic are usually installed functional components, such as a movable core or a high pressure cylinder. When the melted plastic has injected into the mold and not yet solidified, those functional components can be used as a valve of the plastic flowing channel, or a valve of the gas vent of the mold, or remnant after cutting the plastic pieces, or to punch the predetermined holes or troughs on the plastic pieces, or to do the cutting, pressing and filling processes to the plastic pieces. Thus, after the plastic injected into the mold is solidified, the surface of the plastic can be kept smooth and saving the process of removing the pouring opening or the burr of the plastic.
The mold closing and opening of the male and female mold, and the movable core moving back and forth inside the mold, both rely on hydraulic equipment to provide strong driving force. Wherein, the mold opening and closing movement need approximate 120 kg/cm2 to 150 kg/cm2 low pressure oil power provided by the hydraulic equipment. The movable core even needs 600 kg/cm2 to 1500 kg/cm2 ultrahigh pressure oil power provided by the booster installed inside the hydraulic equipment to make sure the movable core functioning well during the processing.
Besides, the conventional hydraulic equipment attached to the plastic molding machine uses a continuously boosting method to increase the oil pressure to high pressure or ultrahigh pressure. However, a special high pressure or ultrahigh pressure valve needs to be installed in the whole oil passage. This special valve costs a lot and is big in volume.
In order to improve the inconvenience of using the high pressure or ultrahigh pressure valve, an intermittent pressure boosting of the hydraulic equipment is applied. However, the intermittent pressure boosting can only provide limited amount of oil to increase the oil pressure during each pressure boosting section. When varieties of mold functional components are linked to the hydraulic equipment, the oil supply for pressure boosting can be insufficient, which may hard to fulfill the ultrahigh pressure requirement of driving the mold functional components.